Rock-drill blowing device



Sept. 23, 1930. w, A, SMITH, SR, ETAL 1,776,604

ROCK DRILL BLOWING DEVICE Filed Oct. 29, 1929 vIf I IN VEN TdRS llfilliawfimit/wn Haiti Izn/ 6 0161 518.

HJJ ATTORNEY Patented Sept. 23, 1930 TUN ST A ATENT OFFICE WILLIAM A. SIflITH, SR., AND JOHN C. CURTIS, OF EAETON, PENNSYLVANIA, ASSIGNORS I TO INGERSOLL-RAND COMPANY, OF JERSEY'CITY, NEW JERSEY, A CORPORATION OF NEIV JERSEY ROCK-DRILL BLOWING DEVICE Application filed 00tober29, lees. Serial no.4oa209.

This invention relates to rock drills, but morev particularly to a blowing device for fluid actuated rock drills of the type in which the hammer piston reciprocates independent ly of the working implement.

The objects of the invention are to selectively admit pressure fluid under full line pressure to the working implement for cleansing the drill hole and to reduce the cost of manufacturing and the expense of maintenance. of devices of this character to a minimum. i I

Other objects will be in part obvious and in part pointed, out, hereinafter.

The figure in the. accompanying drawing. forming a part of this specification 1s a sec-t tional elevation of a rock drill having the invention applied thereto. i

Referring more particularly to the drawing, A designates a cylinder having a piston chamber B therein to accommodate a reciprocatory hammer piston G carrying a forward extension-D which is slidably guided by a front cylinder washer F disposed at the front end of the cylinder A to form a closure for the piston chamber B. r i

The front cylinder washer F may, as illus trated, extend partly into the cylinder A and also into, a fronthead G to centralize the front-head with respect to the cylinder A.

The front head G may boot a known type to act as a housing for chuck mechanism designated byvH for guiding a working im plement J which extends with its rearward end into a cavity K of a chuck to receive the blows of the hammer piston C. The working implement J may be provided with the usual v bore L which extends longitudinally therethrough for conveying cleansing fluid to the hole being drilled for removing the cuttings therefrom. i

i The drill illustrated for the purpose of showing a practical embodiment of the -invention is of the type wherein the working implement J is constantly rotated to shift its position between successive blows of the piston C. The chuck H is therefore provided with introverted ribs 0 which interlock with flutes P in the extension D of the piston so that the piston is free to move longitudinally of the chuck but will be heldagainst rotation with respect thereto. j r i The drill is provided with the usual rotation mechanism comprising a ratchet ring disposed in the rearward end of the cylinder A and having teeth R to act as abutments for spring pressed pawls S carried by a head T of a rifle bar U whichv interlocks with the piston C in a well known manner. The-head T of the rifle bar lies within the ratchet ring Q and carries at its rearward end a trunnion V which is journalled in a back head W seated on the rearward end of the cylinder A,

The rotation ratchet Q and also the head T are disposed near the rearward end ofthe cylinder A, Between these elements and the piston chamber is disposed the valve mecha nism designated generally by X and whereby the distribution of the pressure fluid to the piston chamber is effected. The valve mecha nism X comprises i a valve chest Y in the formof a pair of plates Z and Z). The plate 6 lies adjacent therearward end of the piston chamber B to form a closure therefor and the plate Z is interposed between the plate I) and the rotation ratchet Q for which it forms g seat as well as for the head T of the rifle ar. i c

'Within the plate Z is a valve chamber a to accommodate a distributing valve d for which the plate 6 acts as a seat. The distributing valve d is illustrated as be ing of the oscillatory plate type adapted to rock onan intermediate fulcrum e and. having wings f and g which control inlet passages h and 7' leading from the" valve chamber 0 tothe rearward and forward ends I respectively of the piston chamber B for admitting pressure fluid thereto to actuate the piston C. The exhaust of such pressure fluid from the piston chamber B is effected through a main exhaust port is in the cylinder A controlled by the piston G. y y 1 In addition to its function as a closure for the rearward endof the cylinder A the back head V] also serves as a housing for a throttle valve 0 which may be ofthe rotary type and has a handle or lever p whereby it may be manipulated. Within the throttle valve 0 is a chamber 9 which may be inconstant communication with a source of pressure fluid supply, and in the side of the throttle valve is a port 4 to register with a passage 8 1n the back head.

The passage 8 leads to a supply chamber t in the back head and the supply chamber t communicates with the valve chamber 0 through supply passages 10 in the ratchet ring Q and the plate Z.

The drill may be provided with any well known means for supplying cleansing fluid to the drill hole to wash the cuttings therefrom, as for instance, a water tube '2) which extends from the back head W through the percussive element and intothe boreL of the working implement; Thewater tube may be secured in the back head in any suitable mannerand the water may be supplied thereto by any well known means (not shown).

According .to the present invention the cylinder A, the back head W and the front cylindervwasher F are provided with a blower passage '21) which leadsfrom the throttle valve o'to an annular groove 0a in the front cylinder washer F. The portion of the blower passage to adjacent the throttle valve 0 is so arranged that by rotating the throttle valve 0 the port- 1" therein may be brought .into registry with the blower passage w. In this Way pressure fluid is supplied to the valve chamber a through the annular groove w to supply pressure fluid to the flutes P'from whence such pressure fluid may flow into the bore of the working implement and also rearwardly through the flutes P into the forward end of the piston chamber, it being understood that the flutes P are of such length that their rearward ends will at all times extend into the piston chamber B.

As Will be readily understood from the foregoing description, when pressure fluid is being admitted into the annular groove 00 the supply of pressure fluidto the piston chamber through the usual channels will be cut off. It will be obvious therefore that pressure fluid flowing through the flutes Pinto the forward end of the piston chamber B will tend to drive the piston C rearwardly in the piston chamber. In 'order'to oppose this movement of the piston the cylinder A is provided with a leak port 3/ which affords communication between the blower passage w and the rearward end of the piston chamber B.

The leak port 3/ may be located at any convenient position intermediate the end of the cylinder and the exhaust port 76 and serves to convey pressure fluid into the rearward end of the piston chamber during the blowing operation when pressure fluid is being supplied to the blower passage w. 7 7

Owing to the fact that the piston C has diiferential end areas the pressure acting against the rearward or larger end will predominate over that acting against the other end so that the piston will be gradually moved forward to a point where it will uncover the exhaust port is. To equalize the pressures acting against the piston in this manner obviously causes the piston to move a considerable distance and this has been found to be highly objectionable, particularly where the drill is equipped with rotation mechanism since then any movement of the piston will cause the drill to rotate bodily during the blowing operation, it being understood of course'that the drill is not usually supported by the operator during blowing owing to the presence of dust in the vicinity of the drill. v v

In order to prevent reciprocation of the piston during the blowing operation and to maintain it in a position where it serves as a' closure for the exhaust port the cylinder A is provided with a pair of auxiliaryexhaust ports a and 2 disposed on opposite sides of'the main exhaust port is. The exhaust ports is located rearwardly of the exhaust port 70 and the exhaust port 2 is located for wardly of the main exhaust port 70. The auxiliary'exhaust ports a and 2 are so spaced withrespect to each other that both may be simultaneously slightly uncovered by the piston so that the pressure-acting against its ends may be readily equalized without necessitating any considerable movement of the piston. V

In the operation of the device, whenever it becomes necessary to effect a thorough cleansing of the drill hole, the throttle valve 0 may be rotated from its normal position in which the port a" registers with the passages to the position illustrated in the drawing, in which the port 1" is in registry with the blower passage 20; Pressure fluid will then flow through the blower passage to into'the annular groove :0. A portion of the fluid will flow forwardly through the flutes P into the passage to cleanse the drill hole. At the sametime some aressure fluid will flow through the flutes P into the front end of the piston chamber to move the piston C rearwardly.

Upon the admission of pressure fluid into the blower passage w pressure fluid will also flow through the leak port y into the rearward end of the piston chamber B to act against the corresponding end of the piston C. Owing to the large pressure surface on the rearward end of the piston C the pressure fluid acting thereagainst will move the piston C forwardly until the exhaust port It is uncovered. In this way is provided an escape for the pressure fluidtending to move' the piston forwardly and the pressure in the rearward end of the piston chamber B will then drop to substantially the same value as that acting against the forward end of the piston.

In the event, however, that the pressure acting against the forward end of the piston sure fluid to the annular will momentarily predominate the piston C will be moved only a very'slight distance rearwardly to open the port 2 to wider limits, and the pressure fluid in the front end of the piston chamber will then be reduced to the same value as that acting against the rearward end of the piston. In this way the piston will be held in an intermediate position so that it will lie directly across the exhaust port is. This position of the piston may be maintained with only a very slight movement of the piston. Upon completion of the blowing operation the throttle valve 0 may be rotated to supply pressure fluid to the valve mechanism for actuating the piston and the supply of pressgroove 00 will then be out 01f.

We claim: 1. In a fluid actuated rock drill, the combination of a cylinder having a main exhaust port and a piston in the cylinder controlling the exhaust port, an extension on the piston having flutes therein, a working implement to receive the blows of the piston and having a 'bore therethrough, avalve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, a distributing valve in the valve chamber to control the inlet passages, means for controlling the supply of pressure fluid to the valve chamber, a blower passage leading from said means to the extension and controlled by said means to supply pressure fluid through the flutes to the said bore and to the front end of the cylinder, a leak port affording communication between the blower passage and the cylinder, and auxiliary exhaust ports in the cylinder to equalize the pressure acting against the ends of the piston for holding the piston over the main exhaust port during the blowing operation.

2. In a fluid actuated rock drill, the combination of a cylinder having a main exhaust port and a piston in the cylinder controlling the exhaust port, an extension on the piston having flutes therein constantly communicating with the front end of the cylinder, a working implement to receive the blows of the piston and having a bore in communication with the flutes, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, a valve in the valve chamber to control the inlet passages, a blower passage for conveying pressure fluid to the flutes in the extension, a throttle valve for selectively admitting pressure fluid to the valve chamber and to the blower passage, a leak port in the cylinder for conveying pressure fluid from the blower passage into the rearward end of the cylinder,

and auxiliary exhaust ports in the cylinder and on opposite sides of the main exhaust port to equalize the pressure acting against the ends of the piston for holding the piston over the main exhaust port'during the blowing operation.

V 3. In a fluid actuated rock drill, the combination of a cylinder having a main exhaust port and a piston in the cylinder controlling the exhaust port, an extension on the piston having flutes therein constantl communicatthe valve chamber to the cylinder, a valve in the valve chamber controlling the inlet passages, a blower passage for conveying pressure fluid to the flutes to cleanse the hole being drilled, a throttle valve forselectively admitting pressure fluid to the valve chamher and to the blower passage, a leak port in the cylinder for conveying pressure fluid from the blower passage into the rearward end of the cylinder, and auxiliary exhaust ports on opposite sides of the main exhaust port spaced with respect to each other to be simultaneously slightly uncovered to equalize the pressure acting against the ends of .the piston for maintaining the piston over the main exhaust port during the blowing operation.

In testimony whereof we have signed this specification.

WILLIAM A. SMITH, SR. JOHN C. CURTIS. 

